Rotary machines

ABSTRACT

The disclosure describes rotary machines which comprise two or more rotors which are in continuous sliding contact to the neighboring ones forming working compartments of periodically varying volume. The discription of geometric properties that govern the shape of these rotors, their application to various rotary machines, such as pumps and internal combustion engines, and the discussion of shapes of ports and other practical problems are included.

United States Patent 1191 Park [451 Mar. 26, 1974 ROTARY MACHINES [76] Inventor: Jacob J. H. Park, 659 Chapman Blvd., P.0. Box 8343, Ottawa, Ontario, Canada 22 Filed: Feb. 22, 1971 211 Appl. No.: 117,662

4/1938 Great Britain ..418/196 l/1929 France ..4l8/l96 Primary Examiner-C. J. Husar 5 7] ABSTRACT The disclosure describes rotary machines which comprise two or more rotors which are in continuous sliding contact to the neighboring ones forming working compartments of periodically varying volume.

The discription of geometric properties that govern the shape of these rotors, their application to various rotary machines, such as pumps and internal combustion engines, and the discussion of shapes of ports and other practical problems are included.

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FIG- 25 VVENTO M Alpa/pk PATENTEDMMSIQM V 37991126 SHEET l 8F 4 INVEN TOR ROTARY MACHINES This invention relates to rotary machines comprising two or more rotors with parallel axes, which rotate in the same direction, at the same speed or at a different speed of simple ratio, with the radial edges of the rotors in continuous sliding contact with the adjacent rotor or with the inner peripheral surface of the stator housing, the inner contour of which possesses the form of a twolobed or multi-lobed shape, composed of combination of circular arcs, thereby forming working chambers of varying volume between the said inner surface and the rotor or rotors, or between rotors themselves and can be made to work as a pump, hydraulic power device, turbine, internal combustion engine or compressor.

It is common in rotary machines, efforts were made to eliminate reciprocating movement of the piston machines in order to overcome problems of vibration and complexity of valve control means and improve efficiency by the elimination of periodical momentum change and reversal of the piston. However, most of the rotary machines that have been developed so far have either eccentric rotors or complicated shape and mechanism, and in many instances relative reciprocating movement is still hidden in the process, although it may not be obvious from the overall point of view.

It is the object of the present invention to simplify the geometry of the rotors and improve the operation of the machine by introducing inherently completely balanced and non-eccentric rotors, thus reducing the problem of vibration to a minimum. Another feature of the simple geometry is that the rotary machines of the kind set forth consist only of circles or segments of circles so that all parts of the machine can be fabricated using the very basic machine tools. Further feature of the geometry is that a wide range of design flexibility exists such that the point of contact between the rotors or between the rotor and the inner surface of the stator can be chosen to be either a sharp edge to surface or tangential surface to surface in which case a better sealing between the compartments can be had without further auxiliary sealing means such as vane strips, and also such that the volumetric change versus the rotation angle can be varied to a certain extent. Still another feature of the geometry is that the rotors are solely supported by the straight rotating shaft, therefore no frictional wear occurs in the moving parts except for the shafts and gears where it is relatively easy to keep the said wear at a minimal level.

Further simplification is achieved by combining the inlet and outlet control means with the rotation of rotors and rendering it possible without additional control means. This is accomplished either by the help of auxiliary or main rotors, the rotation of which covers and uncovers the inlet and outlet ports at the appropriate moment in relation to the rotational angle.

In a rotary machine of the kind set forth, wherein the outer stator has a cavity in the form of three cylinders of true circles in line, portion of each said neighboring cylinders superimposing into the next one, and wherein all three rotors are in continuous sliding contact with the next one, or with the inner wall of the outer housing so that the chamber occupying the space within the stator housing is divided into four separate working compartments, the volume of each compartment varying with the rotation of the rotors, the inlet and outlet channels opening into working compartment are according to a further feature of the invention so controlled that within the four working compartments a pump, motor or four-stroke internal combustion process is performed.

Another proposal of the invention refers to a machine comprising of four-lobed outer housing wherein a set of four rotors are in continuous sliding contact with each other or to the inner wall of the stator and rotate in the same direction at the same angular speed whereby five separate compartments of varying volume are formed, the-volume of each compartment changing with the rotation of the rotors, the inlet and outlet channels opening into the working compartments are according to a further feature of the invention so controlled that within the five working compartments a pump, hydraulic power device or turbine process is performed and with additional transfer canals according to further feature of the invention two-stroke internal combustion process is performed.

According to another feature of the invention a structure of two-lobed outer housing wherein a set of two rotors are in continuous sliding contact to each other or to the inner wall of the stator, and rotate in the same direction at the same angular speed whereby three separate compartments of varying volume are formed, the inlet and outlet channels opening into the working compartment are according to a said feature of the invention so controlled that within the three working compartments a gas pump or motor of noncompression application or a hydraulic pump or motor of general application can be performed.

The cooling and the lubrication of the said rotary machines can be achieved by, in addition to the conventional air or liquid cooling and pump pressurized forced lubrication, a simple self pressurizing centrifugal pumping action incorporated within the perfectly symmetric rotor.

Some embodiments of the invention are illustrated by way of examples in the accompanying drawings, in which FIG. 1 shows a set of two rotors with the coordinate axes fixed onto one rotor, thus the rotation of the rotor system can be treated as one rotor stationary and the second rotor making parallel circular movement round the first rotor determining the shape of the said first rotor.

FIG. 2 is the similar condition as FIG. 1 but the coordinate axes are now fixed onto the second rotor to determine the shape of the second rotor.

FIG. 3 is one of the simplest examples of the shape of the two rotors determined by the process shown in FIGS. 1 and 2.

FIG. 4 is an illustration of determining the shape of the first rotor when the second rotor has a rounded tip rather than a pointed tip as it was in FIGS. 2 and 3.

FIG. 5 is an illustration of a case when the radius of curvature of a rotor changed into a different value of radius of curvature.

FIG. 6 illustrated the method of drawing a rotor shape satisfying the continuous sliding contact condition and in addition when all the rotors must be identical.

FIGS. 7 to 10 show the operation of one form of pump or motor composed of three rotors.

FIGS. 11 to 14 show the operation of one form of internal combustion engine.

FIGS. 15 to 18 show the possible variations of the rotor shapes and their effects on the compression ratio.

FIGS. 19 and 20 show variations of internal combustion engine as in FIGS. 11 to 14 but having four auxilliary rotors.

FIGS. 21 to 24 show another form of pump composed of four rotors.

FIG. 25 shows an end plate of the four rotor pump.

FIGS. 26 to 29 illustrate an internal combustion engine consisting of construction similar to that of FIGS. 21 to 24.

FIG. 30 shows an end plate of the two cycle engine.

FIGS. 31 to 34 show yet another form of pump or motor.

FIG. 35 illustrates the rotors with semi-circular crosssection at the tips.

FIG. 36 is a view of the section along line 56 of FIG.

FIG. 37 is a view of the section along line 57 of FIG. 35.

FIG. 38 is a view of the section along line 58 of FIG. 35.

FIG. 39 is an example of a split rotor in which essentially two halves of the rotor are loosely linked together by the shaft assembly.

FIG. 40 is a view through the line 30 of FIG. 18 showing the oil passage for lubrication and cooling.

FIG. 41 is another view of the small rotor showing the range of angle within which the small compartment maintains a constant volume.

FIG. 42 is an example of different type of ports.

FIG. 43 is another example of side slots when the small rotor has the shape as shown in FIG. 17.

FIG. 44 shows the detailed port shape for a four rotor pump.

FIG. 45 is the expanded view of the exhaust port for the two cycle engine.

FIG. 46 illustrates the shape of transfer canal.

FIG. 47 shows the inlet and outlet ports of the two rotor pump.

FIG. 48 is more detailed illustration of a pump for the purpose of showing exact shape of the port openings.

1 GEOMETRY To illustrate that the rotors of simple geometry can be made to satisfy the continuous sliding contact condition the following discussion will help finding the restrictions to be imposed in deciding the shape of rotors. The relative angular speed of the rotors will have to be suitably adjusted to satisfy the sliding contact condition. For simplicity, however, the discussion will be confined mostly to the case of the equal angular speed on all rotors.

As illustrated in FIG. 1 a simple general case of two oval shaped rotors l and 2 are placed side by side, the distance between the two rotating axes being fixed. It is apparent at first that the angle between the two major axes of the rotors should be 90, i.e., the two rotors have a phase difference of 90 in order that sliding contact be maintained with both rotating axes fixed in place.

In order to facilitate the understanding of sliding contact conditions at various angles the coordinate axes are fixed onto one of the two rotors designated by 1. When both rotors are rotating at the same angulartem, thus simplifying the geometry by eliminating rotational movement. The locus of an apex of the second rotor 2 is also shown in the drawing by a solid curve 4 while that of the center of rotor 2 is illustrated by a broken curve 3. When the curve 4 reaches the Y axis another curve 5 is drawn which is the mirror image of curve 4 against Y axis. The oval shape formed by curves 4 and 5 is then taken as the first rotor and the coordinate system is shifted over to the second rotor 2 and fixed onto it in the similar manner as it did to the first rotor and repeat the process as shown in FIG. 2 where the curves 6 and 7 are the loci of the center and an apex of the first rotor respectively and the curve 8 is the mirror image of curve 7. The result is that the two rotors, composed of circular arcs drawn symmetrically to the major axis, with the radius equal to the distance between the axes of the two rotors, difference between the major and minor axes being equal for both rotors, the sum of the semi-major axis of one rotor and the semi-minor axis of the other rotor being the same as the distance between the axis, and rotating at the equal angular speed must be in continuous sliding contact position to each other at all times. This is illustrated in FIG. 3 where R0 a d b c. The terms major and minor axes are used in the sense similar to those of ellipses although the rotors discussed in this section are not ellipses in the mathematical sense.

Advancing to a little more complex case of the apexes not having a well defined angle but having a fixed curvature of radius r, the tip will still describe the same locus as before but accompanying with it, a circle which is tangential to the tip and located toward the direction of the center of the second rotor will also describe the circle. The center of the circle ris assumed to lie on the major axis. When all the loci described by all the points on the small circle are drawn in, they result in a group of loci contained within a donut shaped ring with the inner radius of (R0 r) and the outer radius of (R0 r). This is illustrated in FIG. 4 where the locus 9 is the path of the center of r. and the loci l0 and 1 1 are those made by the two intersecting points 12 and 13 that the circle r makes with the major axis respectively. Thus, the envelopes l4 and 15 are the results of the multitude or loci made by all points on the circum ference of the circle r.

In FIG. 5 the curvature of the second rotor 2 makes a transition to a different fixed curvature of radius r' at the angle B where the curve is still maintaining continuity without a kink but the radius r is greater than r. Then, the circle 16 with (R0 r) radius no longer satisties the sliding contact condition beyond this angle because the portion of the lesser curvature is going to interfere with the circle 16. That is to say, the rotors cannot rotate beyond this angle. To alleviate this problem, another donut shaped ring based on the circle r' is superimposed on the first ring 16. The new donut has the inner and outer radii of (R0 r) and (R0 r) respectively and its center 19 lies at the intersection of line 20 and Y-axis. Only the inner circle 17 of (R0 r) radius is drawn in the figure. The inner envelope of the two composite rings 16 and 17 will now clear the curvatures of both r and r' and yet maintain the contact between the two rotors. The curve 18 is the mirror image of the locus 16 as referenced to the Y-axis. Evidently under these circumstances, the first rotor will be composed of the two different curvatures (R0 r) and (R0 r). For the curves whose centers do not lie on either of the two main axes, the determination of the donut ring is a little more involved than those shown above but will not be treated in this section.

This transition in curvature of the rotor does not have to be a sudden one but a gradual step by step process or even a continuous process whereby a smooth rotor having no sudden change in the curvature or having no discontinuity in the derivative of curvature will result. It must be pointed out that although very smooth rotors can be produced as described earlier, in practice rotors having less number of different curvatures would be more convenient to construct mechanically. Thus the degree of compromise should be determined according to the application.

Utilizing those two geometrical properties, any number of different configurations could be produced by combining the first (point to segment contact) and the second (segment to segment contact where both rotor surfaces are tangential to each other) properties.

As a result of the foregoing discussions the following conclusions may be drawn.

A. No portion of the rotor can have the radius of curvature greater than the distance between the axes of the two rotors.

B. If all the curves involved in the rotors have the radius of curvature equal to the distance between the axes of rotation, then all the tips will have well defined angles and the sum of the angles of the two adjoining tips that slide against each other is 180.

C. The difference between the major and minor axes are equal for the two neighboring rotors and the sum of the semi-major axis of one rotor and the semi-minor axis of the other rotor is equal to the distance between the axes of the two rotors, R0.

D. For the rotors equipped with two distinct radii of curvature on each, the sum of the radii of curvature of the two contacting curves are always constant and equal to R0. This can be generallized to all other cases including the ones with continuously varying curvature and restated as follows.

E. The sum of radii of curvature at the point of contact is always equal to the distance between the rorating axes of the neighboring rotors.

F. The configuration defined by B is the condition under which the maximum ratio of major axis to minor axis is achieved, other parameters being equal. The large value of this ratio is very desirable for some applications.

G. Between the limits of one prescribed by B and that of two true circles in sliding contact (ratiozl any value in the ratio of major axis to minor axis, K, may be obtained. As a special case, the maximum ratio when both rotors must be identical is 1/ 2- l -24.

H. For a fixed value of K, the actual shape of the curve is not determined uniquely. That is, the shape can be varied at will except for the two extreme limiting cases of the ratio, viz. that of one (true circles) and the maximum( condition B).

As a special case of two neighboring rotors being identical, the shape of those can be found by writing two equations of the two circles and solving for the condition giving a single root, as it is the case of two circles meeting each other tangentially and thus making a smooth joint between the different curvatures. For example, if the semi-major axis, a, and the radius of curvature r at the tip were decided, then the equation for the small circle is -0 +y t2 and that for the large circle x (b y) =R and finally from the conditions C and D r R R0 a b where R is the radius of the large circle, and solve for the single root of b (and R0).

The same problem can be solved graphically by drawing two circles 28 and 29 of radius r with centers on the X axis but located such that the far end of the circle will lie at a distance a from the origin as shown in FIG. 6. A 45 line 25 is drawn through the center 26 of a small circle toward Y axis. Next, a larger circle is drawn centered at the intersection 27 of 45 line and Y-axis. The four segment curve consisting of the two different radii of curvature found in this manner will produce rotors in sliding contact position wheh all rotors are identical.

2. A SPECIFIC APPLICATION OF THE GEOMETRICAL PROPERTIES Using the rotors fabricated according to the preceeding discussion a rotary machine can be produced having working compartments of varying volume and inlet and outlet channels connecting to the said working compartments but the opening and closure of the channels being governed by the sweeping of the rotors. In FIGS. 7 to 10 two ports 31 and 32 are provided in each small cylindrical stator compartment, one pair 31 for input and the other 32 for output. The small rotors in this example act as auxiliary means for controlling the port actions and the large rotor is the main one for doing the actual work. The sequence of operation is illustrated at various stages with the interval of 45 between them. As the ports are opened up by the passing small rotors, as shown in FIG. 7, the volumes designated by 36 increase and intake the gas or fluid into the chamber through the shaded ports 31 as they become active. In the following discussion all the ports or passages will appear shaded when they are active. As the volume 36 reaches the maximum as in FIG. 10 ports 31 are closed by the overlapping small rotors 40. When they are reopened as the rotor position assumes that of FIG. 7 again, the alternate ports 32 are now active outputting the content of that volume as it decreases with the rotation. The content that was in volume 36 previously is now in the volume represented by 37. Although the port action was described over the range covering complete 360 rotation, thus considering the inlet and outlet action separately, in actual fact all the ports become active simultaneously, the two said ports 31 inputting and the other two ports 32 outputting. The pump of this type may be regarded as two pumps in parallel and both inlet and outlet actions take place in every of the rotor revolution.

In FIGS. 11 to 14, the rotors and the housing have the similar general construction as in FIGS. 7 to 10 but the ports on one small lobe 49 is sealed and a spark plug 33 installed in that chamber. When the fuel/air mixture is introduced, compressed, and ignited at the appropriate time in relation to the rotation of the rotor system, that said compartment will act as a combustion chamber. Again the sequence of operation is illustrated at various stages, with the interval of 45 between them. The volume of fuel/air mixture is brought into the volume 50 through the port 46 and closed as the volume 50 reaches the maximum by the same process as described in FIGS. 7 through 10. As the rotors rotate further the content of that volume is now represented by 51 of FIG. 11 when the rotor takes up that angular position again. Through FIGS. 11 to 13 that said working fluid is decreasing in volume as was before but since there is no outlet in the decreasing volume the mixture is compressed. At the top dead center or thereabout the compressed mixture is ignited by the spark 33 across the spark gap as illustrated in FIG. 14. As the rotor position returns to FIG. 11 for the third time, the said burning mixture, which is now represented by 52 and increasing through FIGS. 11 to 14, exerts pressure onto the main rotor 43 in the direction of rotation thereby providing the power onto the main shaft. The pressure exerted on the small rotor 42 balances out itself during this time because equal area on both sides of the rotation axis is exposed to the high pressure. After the power stroke, the burned gas is swept out through the port 45 which opens up through FIGS. 11 to 13 as the said gas is now in the chamber represented by 53. What has just been described constitutes a complete four cycle process with all the strokes occuring twice for each revolution. In this system the rotors have dual functions of displacing the content as well as producing volumetric change so that the working mixture content is progressively changing its location as shown in FIGS. 11 to 14. The mixture entering at 50 moves through 51 and 52 sequentially before exhausted via 53. Thus two rotor revolutions are required for a specific volume of charge to complete a four stroke cycle, but because of the four separate compartments all engaged in one of the cycle processes all the strokes occur at any one time. Therefore, one set of rotor system can be regarded as a four cylinder block of conventional four-stroke engine.

The compression ratio of these machines can be approximately determined by the ratio of the large and small cylindrical stator diameters. They are roughly equal in value except for the situation when said diameter ratio is very close to one. However, the compression ratio will also depend on the shape of the rotors and this can be utilized profitably to increase the compression ratio without increasing the ratio of the stator compartment diameters. The increase in the latter generally brings about an adverse effect of decreasing the displacement for a given overall volume of the machine.

For the maximum ratio of displacement to overall volume, rotors that come under category B of Section 1 is ideal. However, at times, the small rotors may become so thin that it would not be practical mechanically as illustrated by 40 of FIG. 15. To overcome this difficulty the small rotors 40 are thickened in FIG. 16. The radius of culvature for the said small rotors are decreased to a minimum without jeopardizing the contact sliding condition. FIG. 17 is another extreme case where the radius of curvature is at the maximum and the shape of the large rotor 41 is adjusted accordingly. FIG. 18 is a compromise between the two. The small rotors 40 are composed of two radii of curvature, one of R and the other very small one 48 just to replace the sharp edged corners 47 that were present in FIG. 17. As an illustration of this effect on the compression ratio, the rotors similar to those of FIGS. 16 to 18 but with the diameter ratio of to I could produce typical volumetric ratios of 5.0, 7.3 and 6.8, respectively.

Two more small rotors could be added as shown in FIG. 19 and 20. In the case of FIG. 20 the large rotor 55 will take the form of four sided curve and rotate at one half angular speed of the smaller rotors 56. One of the additional advantages in this configuration is that two combustion chambers are formed at the opposing ends and the forces acting on the large rotor is always equal in magnitude and opposite in direction, thus providing perfectly coupled force on the main rotor.

3. THE CASE OF ALL IDENTICAL ROTORS For simpler construction, a machine composed only of identical rotors would be attractive. Four identical rotors can be arranged in sliding contact position forming a varying working space bounded by the said rotors. Together with the four-lobed outer housing the inner wall of which is so shaped as to be in sliding contact position with the said four rotors, the said construction produces five compartments of varying volume. In FIGS. 21 and 22 the outer four compartments 60 have increasing volume while the volume of the inner compartment 61 is decreasing. At the position shown in FIG. 22. all the ports are closed as the outer compartments reach the maximum volume and the inner compartment diminishes. The outer and inner compartments are complementary since the volume of the outer housing 62 and the rotors 63 are fixed but the ar rangement of the rotors separate the space into inner and outer compartments. Through FIGS. 23 and 24 reverse process takes place as the outer compartment are now decreasing with the outlet ports open and inner compartment increasing with the inlet valve open. The compression ratio of the inner compartment 61 can be varied over a wide range of design choice by the shape of the rotors while that of the outer four compartments 60 has an upper limit of 1.43. Thus the inner compartment is suitable for high pressure applications such as compressors. FIG. 25 shows an end plate of the stator housing where inlet ports and outlet ports 64 for the outer compartments are so placed and shaped to open and close at appropriate rotor angles for pumping action. For the inner compartment, however, a separate valve control means has to be provided. A simple check valve operated by the pressure differential can be used for this purpose in the case of a pump.

The casing can be extended to leave space between the rotors and the cylinder wall. Then, the pump/motor is treated as a two section machine replacing the four outer compartments with one common outer compartment. For a pump in this configuration, a single check valve similar to the one for the inner compartment pump may replace the four sets of separate ports 64 and 65 of FIG. 25.

The general layout of rotors and outer housing similar to FIGS. 21 to 15 but without the said outlet ports is shown in FIGS. 26 to 30. Because of the missing outlet that was present before, the gas drawn in through FIGS. 26 and 27 is now compressed in FIG. 29. In conjuction with the transfer canals 94 said compression can be utilized to perform an internal combustion engine cycle. The layout of inlet 66 and newly located exhaust ports 67, the spark plug 68 and the transfer canals 94 are illustrated in FIG. 30. The rotors have slots 21 in the vicinity of minor axes as shown in FIGS. 26 to 29 to enhance the exhaust process but the said slots 21 will not degrade the seals between compartments provided that the rotors have rounded tips. -The sequence of the cycle is illustrated through FIGS. 26 to 29 at an interval of 45. The fuel mixture is drawn into the outer compartment while its volume expands as shown in FIGS. 26 and 27 and the ports 66 close as the chambers 60 reach the maximum volume as in FIG. 27, after which the volume decreases resulting in partial compression of the mixture. When it reaches the minimum volume, the transfer canal 94 opens up a passage between the inner and outer compartments as the portions of the said canal are revealed on both sides of the rotor allowing the gas in the outer compartment 60 to flow into the inner compartment 61 through the said transfer canal 94 behind the rotors as illustrated in FIG. 28. As the rotors rotate further, returning to FIG. 26, the transfer canal is blocked by the rotor, as in this case either the entire said canal zone is behind the rotor or the portion not covered by the rotor lies on only one side of the rotor and all the outer compartments 60 are isolated from the inner compartment 61. At this time, the outer compartment is expanding again but the inner compartment is decreasing in volume compressing the mixture just received through the transfer canal as illustrated by FIGS. 26 to 29. At the minimum volume of the inner compartment 61 or thereabout as in FIG. 29, the mixture is ignited and delivers the power to the rotors 63. At the same time the outer compartment 60 has drawn in a fresh charge of mixture and begins to compress as before. Near the end of the power stroke, or just before the transfer canal opens, exhaust ports open and begin reducing the pressure in the inner compartment in preparation for the transfer action. The process results in a two cycle engine, all the strokes occuring twice for each revolution. With this layout a higher ratio of displacement to total volume may be achieved and more even distribution of the heat is another advantage of the system. The exhaust in this system is quite unique from any other two cycle system in that by varying the extent and position of the port 67 on the casing, the beginning and the ending of the exhaust stroke can be adjusted independently of each other or of the transfer action. That is to say, it can be opened before the transfer action starts and remain open during the transfer or can be closed before the transfer is finished to prevent the loss of the .fresh charge of fuel mixture. In many conventional two cycle engines the structure does not permit simple means for closing of the exhaust until after the transfer is finished resulting in loss of some fresh charge and thus lower fuel economy.

The engines can also be constructed using the extended casing as in the case of the pump and the check valves installed. This structure may be simpler in some sense but may be restricted in the range of speed at which the machine can operate.

Further variation of pump or motor is illustrated in FIGS. 31 to 34. The operation of this machine is similar to the three rotor machine. In FIGS. 31 and 32, volume 95 is just beginning to decrease while the volume 96 is increasing. During this time the volume 97 does not change. In FIGS. 33 and 34 the volume 95 is constant while volume 97 is increasing and volume 96 is decreasing. In addition to the simpler construction, this pump has the advantage over the pump in FIGS. 7 to for the smoother and more evenly distributed flow characteristics.

4. SEALS As pointed out earlier, rotors can be designed to render extended tangential contact area near the point of contact improving the sealing between the compartments. However, if tighter seals between the separate compartments are required, vanes may be installed at the tip of the rotor as is well known in the rotary machines. Depending on the shape of the rotor a single spring-loaded vane or a set of several vanes or bands of vanes may be distributed near the tip of the rotor. This will improve the seals between the compartments but care must be excercised to prevent vanes of neighboring rotors from interfering each other. As it is well known that the straight segment vanes are more troublesome mechanically, compared to the piston rings in the conventional reciprocating engines, the rotor shape can be modified to take a curved cross-section or a semi-circular cross-section at the tips. A rotor of finite thickness can be considered as composed of many laminated thin layers. As it was pointed out in G of Section 1, rotor shape can be varied between the limits. Make the outermost layer as two complete circles in sliding contact, and the center layer having a high major/minor axes ratio. Between these two layers they can be designed such that the cross-section of the rotor at the tip would be any shape including the semi-circular form as shown in FIGS. 35 to 38, where rings or bands can be inserted and act as a tight sealing element.

The sealing elements can be made to occupy a large portion of the rotor substance. For example a rotor can be divided into two pieces along the minor axis with some linking element 69 holding the two pieces 70 together in FIG. 39. In this case the two halves of the rotor will always be pulled apart by the centrifugal force but from the view point of the rotor-rotor or rotor-stator system the half piece is pushing against the other rotor or the wall, fulfilling the tight sealing function. The extent of the half piece should be determined by the angular speed and the pressure that the rotors have to overcome to make the tight seals. In the case of an engine the mass of the half piece should be such that the centrifugal force at the designed r.p.m. should just exeed the combustion pressure exerted to the portion of the rotor.

5. LUBRICATION AND COOLING Since the rotor system is inherently balanced and no eccentricity is involved the rotors can be put to work as a simple lubricating and cooling system. In FIG. 40 the oil passage 71 is made through the rotating axis and into the center portion of the rotor. From there the passage is directed toward the apex or anywhere away from the rotating axis where centrifugal force will be exerted to the oil in passage 72. The passage 73 is then directed toward the rotor surface along the line parallel to the rotating axis. Where the passage exits the rotor a matching hole/passage 74 is installed in the end plate completing the circuit. Because of the rotation of the rotor the oil passage to hole interface will meet only once or several discrete times per revolution resulting in a pulsating flow. However, since this simple system utilizes the centrifugal force arising from the distance between the rotating axis to the exit hole, reasonably high pressure oil circulating system can be achieved. During the time the exit on the rotor does not meet the exit hole 24 on the end plate the high pressure oil will lubricate the wall/rotor interface and coupled with the pulsating circulation it will also have the effect of cooling the rotor itself.

6. PORTS AND TRANSFER CANALS The inlet and outlet ports in FIGS. 7 to 14 and FIGS. 19 and 20 were shown as circular for simple approximation. However, when larger ports are required these can be enlarged to the limit determined by the following consideration. The basic rule for a port to function properly in these machines is that any port should be open to any one separate compartment only, at any one time, and conversely, any one separate compartment should have connection to only one port or to ports of the same circuit only. Otherwise, there may be formed a short-circuit between the separate systems. For instance, if the ports were enlarged to an extent shown by 38 or 39 in FIG. 10, at certain angles of the small rotor, both inlet and outlet ports open to the small compartment resulting in a direct flow between the inlet and outlet circuits. In the case similar to FIGS. 7 to 14, there is no volumetric change in the small compartment during the time when the said small rotor is within the angular range indicated by 8 of FIG. 41. Thus, any one of a group of profiles outlining the radial perimeter of the small rotor within this angular range is equivalent to any other as far as the ports are concerned and may be taken as the outer limit of the port profile 98 of FIG. 48. Under this condition both ports bounded by 98 and 100 will be closed when the small rotor coincides with the rotor profile and at other angles each port will be open to either one of the compartment only. For the same reason, the ports in the lower small compartment will also have the same outer limit as above, but in addition, the angle of the tilt 99 of the port profile should be equal for both small compartment, i.e., they should be parallel. The latter restriction ensures that only one port will be open to the large compartment 101 at any time.

In applications where momentary short-circuit is permissible the said ports can be extended further beyond the limit or they can be replaced by side slots as an alternative means of valve action as illustrated in FIG. 42. The side slot system is especially suitable when the rotor shape such as FIG. 17 is employed because in this case fairly large slots can be installed without any shortcircuit or it can be extended to a boundary shown by curve 102 in FIG. 43 when some direct flow is permissible.

Similar reasoning can be applied to the shape of the inlet and outlet ports for the four rotor system. The difference in this case is that the rotor angle between the maximum volume and the minimum volume is 90 compared to 180 of the previous case. This implies that the ports are open between the 90 interval and closed at the maximum and minimum volumes. Assuming the clock-wise rotation in FIG. 44, the inlet port should be open while the rotor moves from 76 to 77. Therefore, the ports will be bounded by curves 79 and 80 and also by the circle 82 since that is the minimum distance from the rotation axis to the rotor peripheral surface. For the same reason outlet port is bounded by 79, 81 and 82.

The exhaust process for the two cycle engine is to be completed in a much smaller angular range compared to 90 of the intake process and if the same procedure as above were applied it would make the exhaust ports too small to be practical. This is shown in FIG. 45 by curves bounded by 83, 84 and 85. To increase the port cross-section in this case, a slot along the rotor minor axis and the same on the end plate are provided as shown by the rectangle 86. The existance of these slots would not seriously degrade seals between the compartments provided that rotors have rounded tips of large enough radius to be sliding contact with both edges of the slot at least once and the tip does not fall between the slot edges loosing contact to both of them.

In contrast to the port requirement set out at the beginning of this section the transfer canal utilizes the opening on both side of the rotor simultaneously. FIG. 46 is an example of the shape for the case when the transfer is to take place within 10 before and after the angle at which the outer volume becomes minimum. The lower end of the said canal is shaped along the rotor profile at i1.0 location asillustrated by 87 and 88, but the shape of the upper portion 89 is not critical as long as there is ample cross-section along the entire length of the canal and at the opening to the outer compartment.

The outer limit of-the ports for the two rotor pump is dictated by the curves 91 and 92 of FIG. 47 on one side and the curve 90 on the other side. The curve 90, however, has a leeway within the range of 8 similar to that of FIG. 41, but because of the fixed nature of 91 and 92, it would be preferable to fix the curve 90 in the midway of the range 6 to maintain equal size of inlet and outlet ports, except when one of the ports is required to be larger for some special purpose.

7. CONCLUSION The foregoing structures are only a few examples of applications of these geometric properties, but the general properties of the periodical volumetric changes can be utilized to replace many of the existing piston machines. For example, the inner compartment of four identical rotors can be made to act as a four cycle engine if the valves similar to those in the piston engine were provided. In this case the outer casing would not be necessary except for the protection purposes or some other additional functions.

In general, a chamber possessing a characteristic of periodical volumetric change can be made to work as a pump when suitably coupled to inlet and outlet valve actions. In most cases a pump can be made to act as a motor, hydraulic power device or a turbine when fluid energy or gas energy is put to work to produce mechanical energy. These machines were often included in the broad sense of the tenn pump throughout this disclosure. Also, an internal combustion engine can be required as a device consisting of a pump or compressor and a turbine, with a combustion stage between them. In fact two units of the three rotor machine in direct drive to each other can be constructed to work as an internal combustion engine, one acting as a compressor transferring the compressed mixture to the next unit which is acting as a turbine, with the combustion chamber provided within the turbine or as a separate unit between the two.

Thus, it is the purpose of this disclosure to show that the simple geometric properties can be applied to produce a set of rotors in continuous sliding contact with each other and these rotors can be put to work as various positive displacement machines, replacing, improving or supplementing existing machines of more complex construction. In addition to the simplicity, because of the absence of eccentricity due to the manyfold symmetricity to the direct and straight drive shaft of the rotors, there is no change of momentum in any part of the structure when rotating at a constant angular speed. It follows therefore, that there should be no limit in the rotation speed imposed by the mechanical jerkiness or reciprocating movement. These rotor systems possess a further advantage that the relationship between the volumetric change and the rotation angle can be controlled, to a limit determined by the geometric restriction, by modifying the shape of the rotors, as pointed out earlier. Also, the fact that the volume of the small compartment can remain constant for a range of angle 8 of FIG. 41 can be profitable for engine designs as it means that the rotor stays longer at the top dead center and thus more complete burning of the fuel mixture can be achieved.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

l. A rotary internal combustion engine comprising an outer hollow body which consists of axially spaced parallel end walls and outer peripheral wall interconnecting the said end walls, and a set of inner bodies supported for turning movement within the outer body and all inner bodies turning on axes parallel to each other, said bodies having respective facing surfaces defining a plurality of variable volume working chambers, said facing surfaces comprising the outer surface of the inner bodies and the inner surface of the outer body which includes a plurality of arched lobe-defining portions spaced according to the rotating axes of the inner bodies, said outer surface of the inner bodies including a plurality of apex portions spaced circumferentially about the axes of the inner bodies, said apex portions engaging alternately the inner surface of the outer body and the outer surface of the adjacent inner body, the shapes of the inner bodies being such that at the point of contact to the adjacent inner body the sum of the radius of curvature of one rotor and the radius of curvature of the adjacent body is always constant and is equal to the distance between the rotating axes of the said adjacent inner bodies, R0, the radius of curvature of any inner body lies within the range from to R0, the outer body having effective intake passage means therein arranged to communicate with the space between the exterior of the inner bodies and the interior of the outer body for consecutively individually inducing a charge of a working fluid into all of said chambers as the inner bodies rotate, said outer body having an outlet port also arranged to communicate with said space for consecutively individually outletting all of said chamber as said inner bodies rotate, said inner bodies being arranged to rotate at the same speed and in the same direction so that the cycle of operation of the rotary machine is determined solely by the movement of the inner bodies, said inner bodies having axially spaced end faces disposed adjacent to,and in sealing engagement with said end walls and having an outer surface with circumferentially spaced apex portions, each of said apex portions having its radially outermost edge disposed substantially at said peripheral wall inner surface of the outer body or at said peripheral outer surface of the adjacent inner body, said apex portions having continuous sealing engagement with said peripheral wall inner surface of the outer body or with said peripheral outer surface of the adjacent inner body such that the space between the facing surfaces of said inner and outer bodies is divided into a plurality of working chambers which individually vary in volume upon relative rotation of the inner body with respect to the outer body, said intake and outlet ports having the shapes and sizes such that rotation of the inner bodies alternately covering and uncovering the said ports at appropriate time in relation to the cycle of operation, the working chambers being open to only one part at any one time and there being no direct passage of fluid between the intake and outlet ports at any time.

2. A rotary internal combustion engine as described in claim 1 in which four strokes of intake, compression, expansion and exhaust are included and one main rotor acts as a working body and two or multiples of two smaller bodies act as auxiliary rotors for controlling the flow of the working fluid and separating the chambers for intake, compression, expansion and exhaust processes. the compression ratio being substantially determined by the ratio of the diameters of the said main and auxiliary rotors.

3. A rotary internal combustion engine as described in claim 1 in which the set of inner rotors are comprised of four identical rotors, and additional transfer canals are provided for passage of the working fluid between the separate chambers at appropriate stage in the cycle such that intake and compression strokes occur simul' taneously at the different chambers and exhaust and transfer occur substantially simultaneously following a period of expansion thereby constituting a two cycle engine, the said inner bodies having slots or cavities at the radially innermost peripheral surface, large enough to enhance exhaust process but narrow enough to be completely covered by the rounded apex portion of the adjacent rotor thus maintaining the sealing between the separate working chambers.

4. A rotary machine as described in claim 1, in which inner peripheral surface of the outer body possesses a convex semi-circular cross-section extending outward and the outer surfaces of the inner bodies possess curved peripheral surface in general, and specifically the same convex semi-circular cross-section at the apex so that sealing engagement can be maintained between the inner surface of the outer body and the outer surface of the inner bodies, the outer surface of the inner bodies having concave semi-circular cross-section at or near the minor axis of the said body such that sealing engagement can be maintained between the outer surfaces of the adjacent inner bodies.

5. Method of designing inner bodies for a rotary machine to secure continuous sealing arrangement between the individual chambers which comprises drawing a set of two arcs of radius R0 such that they will be tangential to the circle of radius (R0 b) and diago nally opposing each other with reference to the center of the rotor, where R0, a and b are the distance between and the circumference of adjacent rotors respectively, there being no solution if the two curves meet within the lobe-defining circle (outer casing) a or b as the case may be but otherwise plurality of different shapes available according to the needs, one extreme case being the curve bounded by the arcs of R0 radius and the lobe-defining circle and the other extreme being the circular arcs with the radius smaller than Ra but such that the two symmetric arcs meet on the lobedefining circle, countless number of varieties existing between these two extreme cases, another example being the smooth continuous curve composed of said boundary curve and two smaller circles meeting the said boundary curve tangentially at the apexes, the shape of the other adjacent rotor is always dependent on the first rotor, once the first rotor is determined the apex of the second rotor is determined by the curvature of the first rotor at the minor axis and is the remainder of R subtracted by the said radius of curvature of the first rotor, the curvature at the minor axis of the second rotor is again what remains from Ro subtracted by the circles are joined together to produce the second rotor. 

1. A rotary internal combustion engine comprising an outer hollow body which consists of axially spaced parallel end walls and outer peripheral wall interconnecting the said end walls, and a set of inner bodies supported for turning movement within the outer body and all inner bodies turning on axes parallel to each other, said bodies having respective facing surfaces defining a plurality of variable volume working chambers, said facing surfaces comprising the outer surface of the inner bodies and The inner surface of the outer body which includes a plurality of arched lobe-defining portions spaced according to the rotating axes of the inner bodies, said outer surface of the inner bodies including a plurality of apex portions spaced circumferentially about the axes of the inner bodies, said apex portions engaging alternately the inner surface of the outer body and the outer surface of the adjacent inner body, the shapes of the inner bodies being such that at the point of contact to the adjacent inner body the sum of the radius of curvature of one rotor and the radius of curvature of the adjacent body is always constant and is equal to the distance between the rotating axes of the said adjacent inner bodies, Ro, the radius of curvature of any inner body lies within the range from 0 to Ro, the outer body having effective intake passage means therein arranged to communicate with the space between the exterior of the inner bodies and the interior of the outer body for consecutively individually inducing a charge of a working fluid into all of said chambers as the inner bodies rotate, said outer body having an outlet port also arranged to communicate with said space for consecutively individually outletting all of said chamber as said inner bodies rotate, said inner bodies being arranged to rotate at the same speed and in the same direction so that the cycle of operation of the rotary machine is determined solely by the movement of the inner bodies, said inner bodies having axially spaced end faces disposed adjacent to and in sealing engagement with said end walls and having an outer surface with circumferentially spaced apex portions, each of said apex portions having its radially outermost edge disposed substantially at said peripheral wall inner surface of the outer body or at said peripheral outer surface of the adjacent inner body, said apex portions having continuous sealing engagement with said peripheral wall inner surface of the outer body or with said peripheral outer surface of the adjacent inner body such that the space between the facing surfaces of said inner and outer bodies is divided into a plurality of working chambers which individually vary in volume upon relative rotation of the inner body with respect to the outer body, said intake and outlet ports having the shapes and sizes such that rotation of the inner bodies alternately covering and uncovering the said ports at appropriate time in relation to the cycle of operation, the working chambers being open to only one part at any one time and there being no direct passage of fluid between the intake and outlet ports at any time.
 2. A rotary internal combustion engine as described in claim 1 in which four strokes of intake, compression, expansion and exhaust are included and one main rotor acts as a working body and two or multiples of two smaller bodies act as auxiliary rotors for controlling the flow of the working fluid and separating the chambers for intake, compression, expansion and exhaust processes. the compression ratio being substantially determined by the ratio of the diameters of the said main and auxiliary rotors.
 3. A rotary internal combustion engine as described in claim 1 in which the set of inner rotors are comprised of four identical rotors, and additional transfer canals are provided for passage of the working fluid between the separate chambers at appropriate stage in the cycle such that intake and compression strokes occur simultaneously at the different chambers and exhaust and transfer occur substantially simultaneously following a period of expansion thereby constituting a two cycle engine, the said inner bodies having slots or cavities at the radially innermost peripheral surface, large enough to enhance exhaust process but narrow enough to be completely covered by the rounded apex portion of the adjacent rotor thus maintaining the sealing between the separate working chambers.
 4. A rotary machine as described in claim 1, in which inner peripheral surfaCe of the outer body possesses a convex semi-circular cross-section extending outward and the outer surfaces of the inner bodies possess curved peripheral surface in general, and specifically the same convex semi-circular cross-section at the apex so that sealing engagement can be maintained between the inner surface of the outer body and the outer surface of the inner bodies, the outer surface of the inner bodies having concave semi-circular cross-section at or near the minor axis of the said body such that sealing engagement can be maintained between the outer surfaces of the adjacent inner bodies.
 5. Method of designing inner bodies for a rotary machine to secure continuous sealing arrangement between the individual chambers which comprises drawing a set of two arcs of radius Ro such that they will be tangential to the circle of radius (Ro -b) and diagonally opposing each other with reference to the center of the rotor, where Ro, a and b are the distance between and the circumference of adjacent rotors respectively, there being no solution if the two curves meet within the lobe-defining circle (outer casing) a or b as the case may be but otherwise plurality of different shapes available according to the needs, one extreme case being the curve bounded by the arcs of Ro radius and the lobe-defining circle and the other extreme being the circular arcs with the radius smaller than Ro but such that the two symmetric arcs meet on the lobe-defining circle, countless number of varieties existing between these two extreme cases, another example being the smooth continuous curve composed of said boundary curve and two smaller circles meeting the said boundary curve tangentially at the apexes, the shape of the other adjacent rotor is always dependent on the first rotor, once the first rotor is determined the apex of the second rotor is determined by the curvature of the first rotor at the minor axis and is the remainder of Ro subtracted by the said radius of curvature of the first rotor, the curvature at the minor axis of the second rotor is again what remains from Ro subtracted by the radius of curvature of the first rotor at the major axis or apex of the said first rotor, alternatively, ceters of all the curvatures involved in producing the first rotor can be used to produce the shape of the second rotor, from each center of radius of curvature a circle is drawn with radius equal to the difference between Ro and the radius of curvature drawn at that point for the first rotor, when all these circles are drawn the arcs of the each circles are joined together to produce the second rotor. 